Developmental senescence is characterised by the sequential degradation of the cells
of plant tissues, including the decomposing of the photosynthetic apparatus and the
initiation of the chloroplast autodegradation processes. Although the photosynthetic
apparatus incorporate a large number of iron containing cofactors, little is known
how the potentially oxidative stress generating effects of the iron nuclei liberated
from the cofactors at the decomposing of the photosynthetic apparatus is prevented.
We applied Arabidopsis thaliana model, grown under optimum and non-toxic supraoptimum
iron supply. Samples taken at multiple stages after the initiation of senescence were
cryofixed. Cryosectioned, lyophyilised samples were studied by high resolution, low
energy X-ray fluorescence (LE-XRF) imaging. The transient accumulation of iron that
found to be independent on the iron nutrition suggests a transient storing of iron,
liberated from the photosynthetic apparatus in ferritins.
This work was supported by the grant financed by the National Research, Development
and Innovation Office, Hungary (NKFIH K-135607) and by the beam time allocation No.
20225238 of Elettra-Sincrotrone, Trieste, Italy.
